Factor D is a highly specific chymotrypsin like serine protease that is a rate limiting enzyme in the activation of the complement alternative pathway (Katsche et al., 2012, J Biol Chem 287:12886-12892). Increased activation of the alternative complement pathway has been found in drusen, cytotoxic deposits present on the Bruch's membrane, which are associated with the development of age related macular degeneration (AMD) (Damico et al., 2012, Arq Bras Oftalmol 75:71-75).
Inhibitors of Factor D are being developed as therapeutics to prevent activation of the alternative complement pathway, thereby inhibiting inflammation and cytotoxic activity of the activated complement components (Tanhehco, 1999, Transplant Proc 31:2168-2171).
Activation of the alternative complement pathway is typically measured by adding human serum to rabbit erythrocytes. Next, intact erythrocytes and cellular debris are pelleted by centrifugation and lysis is determined by measuring the absorbance at 412 nm arising from the release of hemoglobin into the supernatant.
Citation of a reference herein shall not be construed as an admission that such is prior art to the present disclosure.